Booster detonator



May 21, 1929. s. B. LARGE BOOSTER DETONATOR Filed Feb. 23, 1927 ijXMLL/F fmwhw .J H I. W1 w though certain of ventlon.

: Generally,

" favor 1 as an provides degree. handle Patented May 21, 1929.-

- ..UNITED STATES. PATENT 1,713,838 OFFICE.

A I V I 1 w SYLV ESTER B. LARGE, .OF TAMAQUA, PENNSYLVANIA, ASSIGNOR TO ATLAS POWDER COMPANY, OF WILMINGTOH DELAW-ARE'A CORPORATION 01 DELAWARE.

' nooszrnn nrironaron.

. Application filed. February as, 1927. Serial Nth 170,265.

My invention relates especially .to the manufacture and general assembly of that type of detonator or blasting cap commonly known as the compound or booster type, its advantages may be a; plied to other types. It dealsparticularfy with the promotioniof safety'in' the handling, storage and use of such detonators, and makes possible the use in booster detmight otherwise be too sensitive, though it greater safety ih the manipulation of any type of primer. Its most convenient application is in connectidn with non-crystalline or finely crystalline masses which maintain. suspension .in water to a fair by the methods heretofore em the invention maybe of primer by suitable the scope of the in:

ployed. However, applied to any type manipulation within Itis generally detonator of the compound or booster type, when properly made of. proper materials, is an improvement over the usual fulminate-chlorate cap. Sucha cap usually contains. two or more separate charges, though it is possible to mix the booster material with the initiating material in some cases, as one charge. The booster charge is usually composed of such. materials as tetryl, hxanitrodiphenylamine, picric acid,

- nitrostarch, n itro'manmte or nitrocellulose.

The ,mitiator may be fulminate of mercury, a heavy metal azide or explosives of their properties, or mixtures oi such explosives.

from combustion, through ignition, to maximum detonation in aJvery short time,and. under slight confinement,

as an initiator for maybe considered as having possibilities compound detonators, oras. a sole charge for detonators' Fulminate of mercury has found much initiator because it has a rela tively low ignition temperature, is easily made and, while verf sensitive, can be ma nipulated in the dry state with a-limited hazard, -As an initiatoig however, it is inferior to some other substaifdes such as eertain heavy metal azides, .for instance; This is'illustrated 'by the Well-known fact that very much smaller charges' of. certain heavy metal azides, than of fulminate of mercury,

7 somewhat more hazardous.

rimers, which of manufacture. These types aremost difiicult to agreed that a blasting cap an explosive which will pass are required to detonate the secondary or Merof much greater of mercury, but, manipulation, is

base char e m compound detonators. curous azlde 1s an mltlator effectiveness than fulmmate under certain forms ofinferred, however,

been done commercially. Further, in a finished detonator, tests have shown itto be Fig. 1 is a sectional diagrammatic viewv illustrating a .detonator in its initial stage Fig. 2 is a like view mediate stage in the manufacture of the detonator; and

Fig. 3 is a like view illustrating the finalform of the detonator.

Like numerals designate corresponding elements in all of the figures of the drawing.

In the drawing, 1 deslgnates the detonator shell and 2, the base or booster charge, which, for purposes of convenience, I will hereinafter refer to as tetryl, that any suitable material may be employed in this relation. In the'initial pressing of the base charge 2 into the shell, a cehtral indentation or depression 2 maybe formed in the charge in the manner disclosed in my Itis not to bethat it can not be handled successfully in the dry state since this has illustrating an interthough it is clear.

copending'application SerialNumberl64,802.

filed on the 31st day of J anuary, 1927. However, it is to' be understood that this base charge may be formed with any lesser de; gree of indentation up to-"a perfectly flat surface. I prefer the cause less initiating charge isthen required,

owingv to the increasedarea of contact be- .tween "the initiating charge and the base charge. Further, with some initiatin charges, it may be desirable to maintain portions of v with the shell Wall, andin such case the central indentation is of utility for that purpose. 7 In Fig. 1, the initiating charge 3 is shown as being contained'in a tube 4. A plunger 5' is adapted to. operate within this tube. The charge 3 may, and

sist of mercurous azide. Mercurous azide large indentation bethe initiating charge out of contact' preferably. will, conmay be made by combining sodiumazide and a It precipitates as a, very fine wh te mass,

which cakes on drying, and exists as a dusty mercurous salt. in aqueous solution.

white'powder bn breaking up the cake.

my procedure the precipitated azide is washed by decantation, then run on to a sucto prevent an most conducive to convenience in subsequent tion filter and reduced to a moisture content operations. It may, in this wet condition, be stored indefinitely in rubber bags. The described wet azide is placed in a suitable container and the tube 4 is made to contain the desired quantity of azide by immersion in the wet mass of the same in the container.- This proper quantity may be obtained by immersion of the tube to the proper depth and the action of capillarity, orby the regulated action of the plunger" It is, of

course, obvious that other means of tube loading might be resorted to I without departure from the invention. After the tube is loaded, it is inserted in the 'detonator shell.

A. protective tube or sleeve 6 maybe used possibility of smearing the side walls of t e shell with the azide. However, the invention is not limited to the use of a protective'tube of this character. After the tube 4: has'be'en inserted in shell 1, to

"the proper depth, a slow movement of the piston 5' serves to eject the wet mercurous sonable numberof at the same time.

azide on to the tetryl and into the indentation 2*; The tube is then removed for reloading. and for a; repetition of the opera: tion. It will be understood that any rea-' tubes may be operated Following the foregoing the wet azide in the shell may be partially ilriedor the-shell pass immediately to the next operation.

I ThlS consists in charging a dry explosive,

which may be'an ignition transmitter, such as lead trinitroresorcinate, or a' combined ignition transmitter and partial initiator as fulmin'ate' of .mercury.-. .Upon subsequent ressing of the entire assembly, .the moisture in the azide charge penetrates the upper dry charge sufliciently to desensitize it materially, yet bya reasonable control of the amount of moisture in the azide, the upper charge does not become sufliciently moist at its upper surface to smear the press points. The

detonators so made are very insensitive through subsequent operations and until they are-finally packed in their ultimate containers. At this stage they may be dried out sub ection to warmth or warmth and re-' duced ressure' 4 .4

f It wlll be obvious that when the drytop charge ple), is pressed on the wet intermediate charge (mercurous azide, 'for example) it tends to mix partially with it, yet no azide penetrates entirely to the surface. Thus,

I evenif a very sensitive intermediate initiator. is used, it is entirely covered up by the sensitive or other topcharge.

t is

promotes safety} 'in usev without sacrithe advantages resulting from the use (fulminate' of mercury, for exam-.

of'more effective-initiators than, mercury fulminate.v

An example pf a satisfactory charge for p commercial detonators made under this process is: (l) a base charge of 0.4 grams tetryl; (2) an intermediate initiator charge of 0.10

'- grams (40'60 niercurous azide-water; and

of 0.3 grams fulminate of mercury.

While for purposes of illustration, described the charges as consisting of tetryl, pon the one hand,-and fulminate-mercur- I havea (3) a top ignition and initiation vaid charge ous azide, upon the other hand, it is to be understood that the principle involved and which forms the real' substance of the invention, goes far beyond the use of an partures,l fulminate-l'ead azide mixtures, or any other suitable combined charge recognized in the 'art as applicablefin this relat1on,may be employed. Furthermore by the use of the term mixtures, I intend to include either the actual intermixin stances of which the' initiating charge is composed, or the superimposing of one of these substances upon} the other, as herein of'the sub-'- disclosed. Ihave chosen mercurous azide as" thev example to be stressed because it serves;

excellently to resent the idea involved. The

application 0 mercurous azide is materially aided by my invention. Some other possible ioo in ia r are sosensitive and hazardous when dry, that they can hardly b ed without the employment of this invention.

"It is commonly recognized in the art that "the wet loading of initiators and their con sequentdesensitization during their uent handling in other operations, is lii ghly initiators has presented great inconvenience and difliculty becausea condition of wetness, 'suflicient'to properly desensitize thefdeton'a tors, resulted in wetting the press points during' tf he pressin operation If the loose pointsmndcausethe primer moist be ore pressing, it is almost sure to-wvet the press explosive to adhere to and cake on them duresirable.' However, the charging ofwet.

ing the pressing operation. Upon the other hand, initiators which are of a fine, dusty nature when dr are almost impossibleof application in t e dry state;

' Another. advantage of this invention ,is

that when Y a --mercury fulminate-lead azide initiating charge is employed, the lead aside may be'maintained,'bythe presence of the tetryl, out of actual contact with; the wall of the shell, only the mercuryiulminata .7 actually contacting withthe wall of shell, after the final 'pressing of the char This-is'of importance,

for the reason g usually employed, copper or gilding metal -shell s, WhlChl are cheap and easlly drawn, are not practically resistant to lead azide,

fwhile'they are resistant to fulminate of mer-- cury. Thus by my method all-of the advantages of wetting and desensitizing are had,l with the additional advantage that deterio ration of the shell, due to the presence of .lead azide, is'prevented. V

' My invention accomplishes the following important points It combines convenience and low cost with the desired safety resulting from wet loading and wet subsequent handling; it reduces "to a minimum the amountof' dry initiator necessary in a factory; and it makes possible the application 1 of'initiators which, on account of physical condition or great sensitlveness, are' not practical in dry methods.

While I have described a form of my invention in detail, and have given a' specific example and sketch, it will be understood that many changes may be made therein Without departing from the spirit of my in vention, The detonator shell may be oi any metal suitable to the base; andv initiating charges it is desired to use; the loading tubes may be of glass, rubber, metal, celluloid, etc., depending upon the particular situation involved; the tubesimaybe charged and dis:

- charged in many ways; andthere is a very wide range of explosives which may be used as base charge,-intermediate wet charge and top dry charge. My invention, generally, does not involve materials but methods, and

these methods have been clearly explained.

f. apply. my procedure to. detonators which Further, it is within the scope of my invention, and it is here so stated, that I may contain only one initiating charge on top of the base charge or contain only one charge then loadthe base charge normally, add the ter to the empty she altogether. In the former case, I might desire t'o'apply a dry initiator only, in the charging operation, but have lowered sensitiveness in subsequent operations. I, would proper amount of water on topof it, and

charge the initiator thereon. In the latercas e, I would add the roper amount of walil and charge, in one charging, part orrall of the detonator compositio ters Patent is:

p 1. The hereindescribed method of manubooster detonators which consists of a base charge into a shell, then said shell loading ontop -of the base charge a moist charge-of a, substance .of initiating power and then loading a dry charge of easily ignited explosive material upon the moist charge, and permitting the moisture from the moist charge to penetrate the dry charge, to desensitize the same, for a limited period of time. 7

' 2. The herein described method of manufacturing booster detonators which consists of loading a base charge into a shell, loading a moist-charge of a substance of initiating power upon the base charge, and finally loading a dry chargeupon the base charge and pressing the whole, while maintaining wall of the shell at all-times.

3. The herein described method of manufacturing booster detonators which consists of loading a base 'charge into a shell and forming a cavity in said base charge,- load-. ing a charge of a moist initiatory explosive into the cavity of the base charge and then loading a charge of dry ignition material upon the moist initiatory material and pressing the whole in place.

4. The herein described method of manufacturing booster detonators which consists of loading a base charge into a shell, then loading a charge of amoist initiating material into'a cavity formed in said base charge, material being of a nature to attack the metal of the shell and then load' ing a charge of ignition material uponthe "moist inltiatory material, permitting the said initiatory moisture from the initiatory material to penetrate said dry material'and desensitize the same for a limited period of time. 5. The hereindescribed inethod of manufa turing booster detonators, :which consists of loading one part of the charge t ereof into a shell in a moist state and ther after pressing'a substantially dry charge'thereon the molsture from the-first named part of the charge penetrating said dry charge and desensitizing the samepressing operations.-

- 6. The herein described. method of manufacturing of e ectm a moist charge into a blasting cap shell om a'tubular container of a nature to enter said shell anddeposit said moist charge without smearing the sides of pressing a charge.

7. The herein 'facturing blastin dry charge upon said moist escribed method of manularcontainer having an open end of a size during subsequent caps, which consists of. placing a paste e'moist charge in a tubuthe. moist charge out of contact with the ooster detonators, whichconsists with said moist charge, and then adapted to enter a blasting cap shell, entersaid tubular container into said shell cient distance topermit the moist char to be ejected at a low oint inthe shell wit out smearing the si es of said shell w th said moist charge, then depositing a dry charge upon the moist charge-and then compressing the whole. 7

- 8, The herein described method of manu-.

facturing blasting caps, which consists of placing a paste like moist charge in a tubular container having an open endof a size adapted to enter a blasting cap ,shell, enter-' ingsaid tabular container into said shell a,

suflicientdlstance to permit the moist charge to be ejected at a low point in the shell-without smearing the sides of said shell with said moist charge. Y o

9. The herein-described method of manufacturing blasting caps, which consists of loading a base charge into an elongated methe shell and then loading a dry charge upon said moist charge, and thereafter pressing the whole, the moist charge being in such amount as o be" contained wholly within the cavity of t e base char e and out of contact cavity a moist charge. of a material of a nature likely to with the shell, the molsture' from the base charge penetrating the dry charge and deeration.

In t'estimony' whereof he aifixes his signa 'ture. v V

J SYLVESTER B. LARGE.

sensitizing the same during the pressing op- 

